1. Field of the Invention
This invention relates to tools for installing and replacing tubeless tire valve stems, and more particularly to a method and apparatus for installing and replacing tubeless tire valve stems without requiring removal or separation of the tire from the wheel rim.
2. Preliminary Discussion
Tubeless or pneumatic tires were first introduced in 1947 by B.F. Goodrich, Inc. Such tubeless tires have an inner rubber liner rather than a separate inner tube, and incorporate a rim bead, a stiffened molded edge section, usually formed by high tensile steel wire hoops embedded in the two inner edges of the tire. The bead conforms to and fit against the rim seat or inner ledge portion of a vehicle""s wheel rim to hold the tire to the rim. Upon inflation, an airtight seal between the rim seat and the tire bead is created. Provided there is no defect in the rim or tire, once the tire is properly inflated on the rim with a tight uniform seal between rim seat and the tire bead, there is no way for air to be forced into or out of the wheel, except through an inflation valve.
Since there is no inner tube, the inflation valve stem is usually secured in an annular opening provided through the rim for the valve. Conventional tubeless tire valve stems are comprised of an elastic rubber body or casing, which casing houses a valve core, typically comprised of a spring biased valve mechanism. The rubber casing typically includes an upper portion surrounding the protruding metal threaded end of the valve core, which portion can pass readily through the rim opening and may be slightly downwardly and outwardly tapered. The upper portion merges toward its lower end opposite the threaded end with a conical portion of rapidly increasing diameter, the conical portion being adjacent to or accommodating at its lower end an annular bead with a diameter slightly larger than the diameter of the rim opening. Below the annular bead is a substantially annular flat-bottomed groove sized to cooperate with and sealingly interfit with the rim opening. Finally, such annular flat-bottomed groove portion merges at its lower end into an enlarged annular flange or bulbous head having a substantially larger diameter than the rim opening.
Ordinarily, valve stems are installed from the inner side of the rim by pulling the valve, threaded end first, through the rim opening using a suitable pulling tool until the bulbous head of the valve stem is seated against the inner, or tire, side of the rim and the flat-bottomed annular groove is seated or secured in the rim opening. The inherent elasticity of the rubber body seats or anchors the valve in the rim opening, and in addition, since in most valve stems the valve is not bonded tightly or directly to the enlarged head or base, such head will resist dislodgment by the high pressure within the tire since it can mushroom outwardly along the inner side of the rim.
The valve stems just described are commonly used because they are relatively inexpensive, easy to install, light, and wear well. However, eventually they may become deformed, bent, or cracked, or the rubber casing will begin to lose its elasticity and leak. Tire valve stems on trucks, farm equipment or other construction-type vehicles may also experience more severe damage at a higher rate than a typical valve stem on a passenger vehicle. Since the bulbous head portion cannot be easily forced through the rim opening from the outer side of the rim without damaging the rubber casing, in most cases, when it is required to remove or replace an inflating valve stem, the tire must be unseated or dislodged from the rim in order to gain access to the inside or tire side of the rim, thereby breaking the airtight seal between the bead seat and bead. Since special equipment is usually required to correctly seal a tubeless tire to a rim, and every time the seal is broken there is an increased likelihood of later leaks, the removal of the tire from the rim can result in prolonged downtime and significantly delay or hinder use of the vehicle. Thus, there is a need for an improved tool wherein a cracked, bent, or otherwise damaged valve stem can be replaced xe2x80x9cin the fieldxe2x80x9d without requiring that the tire be removed from the rim and wherein the valve stem could be inserted into the rim opening of a tubeless tire from the outer side of the rim and tire, rather than from the inner side.
3. Description of Related Art
Numerous tools and methods for repairing damaged valve stems without requiring that the tire be unseated from the rim are known. For example, U.S. Pat. No. 2,652,858 issued to R. V. Snyder entitled xe2x80x9cRepair Unit for Tire Valve Stems,xe2x80x9d teaches a method wherein the damaged portion of the stem is cut away or removed and a repair unit is clamped over the undamaged or remaining portion of the stem. In U.S. Pat. No. 3,863,697 issued to R. C. Brown, entitled xe2x80x9cInstant Valve Insert,xe2x80x9d the entire stem except for the old valve plug is broken off and a new valve having an anchoring means is slipped through and secured to such plug. While such solutions are useful in an emergency, they only provide temporary relief, and still require that eventually a new stem be inserted from the inner side of the tire in the usual manner.
U.S. Pat. No. 3,255,520 issued to J. A. Jerdon, entitled xe2x80x9cAutomobile Tire Stem Removing and/or Inserting Tool,xe2x80x9d discloses a lever having a pivot, wherein the end of a valve stem is screwed to a threaded rod attached on the end of the lever, and wherein the lever is used to forcibly pull a valve out of the rim opening. Although such device is apparently useful in removing valve stems, it would be difficult if not impossible to use such device to push a stem through the rim opening without tearing or damaging the rubber casing covering the stem, which casing is not compressed prior to insertion.
Other known valve stem installing tools include various means for forcing a stem down an elongated and sharply tapered nozzle, such as U.S. Pat. No. 3,750,258 issued to J. J. Sampo, entitled xe2x80x9cInsertion Tool for Tire Valve Stems,xe2x80x9d and U.S. Pat. No. 4,765,048 issued to B. M. Hokanson, entitled xe2x80x9cValve Stem Inserter.xe2x80x9d Such tools force the stems through long tapered nozzles having an inner diameter on the far end that is less than the diameter of a rim opening using a pusher rod or other pushing tool, thereby gradually compressing the bulbous flange of the stem such that it may be inserted into the rim opening from the outside. Although such tools employ a lubrication means, they are generally difficult to operate since a very large amount of force is required to compress the flange and gradually push the stems down the tapered nozzles. Other similar devices employ some additional means to facilitate forcing of the stems down a tapered nozzle. For example, U.S. Pat. No. 3,387,354 issued to H. J. Mossberg, entitled xe2x80x9cValve Inserting Device,xe2x80x9d employs a pusher rod attached to a notched trigger handle. U.S. Pat. No. 4,807,343 issued to T. P. Wadsworth, entitled xe2x80x9cTubeless Tire Valve Stem Inserter,xe2x80x9d also employs a trigger mechanism, attached to a pusher rod using grips to force the rod forward. Finally, U.S. Pat. No. 5,097,580 issued to A. J. Story, entitled xe2x80x9cApparatus for Installing and Removing Valve Stems,xe2x80x9d discloses a valve insertion and removal tool having a tapered elongate tubular body, with the top end fitted to an air piston assembly. Although such a device would make it easier to force the stem down a tapered tube, it is only useful in a garage or other area where a suitable source of power for the operating piston is available.
While valve assemblies for tubeless tires that can be installed from the outer side of the rim are also known, such as disclosed in U.S. Pat. No. 5,211,782 issued to D. Thelen, entitled xe2x80x9cValve Assembly for Tubeless Tire,xe2x80x9d such alternative valve structures are more expensive and generally are less preferred than standard tubeless tire valves. Thus, despite the continued progression of the prior art, there is still a need for an inexpensive tool that can be used to manually insert and/or remove standard valve stems from the rim opening of a tubeless tire quickly and easily and without damaging the rubber casing covering the stem.
The present inventor through trial and error has developed a tool which overcomes many of the disadvantages of prior valve insertion tools. In the preferred embodiment of the invention, rather than pushing the valve stem down an elongated, tapered nozzle, the present inventor utilizes an untapered tube sized to fit into a wheel rim opening in combination with a short tapered attachment, which allows the stem when lubricated to be easily pulled, rather than pushed, into the untapered tube. Such pulling motion is accomplished simply by attaching the valve stem to a threaded rod, which when turned in conjunction with a holding member, easily pulls the stem through the tapered attachment into the untapered tube. Thus, using the present invention, it is no longer necessary to force the stem down an elongated tapered sleeve to the bottom edge of said sleeve, since the stem is simply pulled into the sleeve from the rim insertion end through a short tapered attachment. Such attachment is then removed, and the stem is in position to be inserted into the rim opening. Of equal importance and significance to the invention is the fact that due to the ease of use, no supplemental devices such as trigger mechanisms, ratchet systems, pistons, or other power sources are required to accomplish the method. Such tool can also be used to easily remove a cracked or leaking valve stem. Finally, the invention is significantly less inexpensive to manufacture and produce in comparison prior art insertion tools.
It is an object of the present invention to provide a method and apparatus for installing and replacing valve stems in the rims of tubeless tires.
It is a further object of the present invention to provide a tool which can be used to insert and remove valve stems from the outer side of a tire rim, rather than the tire side.
It is a still further object of the present invention to provide a tool for installing valve stems which does not require that the wheel be removed from the vehicle or that the tire be unseated from the rim during such installation.
It is a still further object of the present invention to provide a tool which is simple and inexpensive to manufacture, easy to use, and does not require an outside power source to operate such tool.
It is a still further object of the present invention to provide a tool which can be used to install or remove valve stems of various sizes.
It is a still further object of the present invention to provide a tool which allows a relatively unskilled vehicle operator to replace a tubeless tire valve without the cost of time and labor associated with hiring a skilled professional to remove the wheel, unseat the tire, change the valve stem, reseat the tire, and replace the wheel.
It is a still further object of the invention to provide a method of replacing tubeless tire valves which when used with appropriate equipment can be carried out easily and quickly by unskilled labor or the owner of a vehicle him or herself.
It is a still further object of the invention to provide a method of replacing the valve stem in a tubeless tire without requiring access to the tire side of the rim and without any complicated or costly equipment.
It is a still further object of the invention to provide a simple, safe and effective method and apparatus by the use of which the valve stems of tubeless tires may be replaced without dismounting the tire.
Still other objects and advantages of the invention will become clear upon review of the following detailed description in conjunction with the appended drawings.
An improved method and means for replacing damaged and defective valves in tubeless tires without having to remove the tire from the rim is provided in which, after the old or defective valve stem is removed from the tire, preferably by pulling from the tire by use of a threaded puller rod comprising a portion of the new valve insertion apparatus of the invention, the new valve sized to replace the old valve is threaded onto the end of a thin rod provided with a force or leverage handle at the end and dimensioned to pass through an insertion tube having an end dimensioned to fit into the valve opening in the tire rim and an opposite end having a larger diameter and an internal beveled or funnel shape leading into a reduced internal diameter portion. The pulling rod is passed through the insertion tube from the smaller end and attached by matching internal threads to the external threads of the new valve stem, the exterior of the valve stem is lubricated and then through the application of tension applied to the pulling rod, the valve stem is pulled through the conical section of the insertion tube into the main section of the insertion tube which has a slightly lesser diameter than the rim opening. The small end of the insertion tube is then placed in or adjacent to the rim opening and the valve stem is pushed from the insertion tube into the exterior of the tire. The insertion tube is then removed from the rim opening and the pulling rod is used to pull the valve stem back through the rim opening until the annular seat groove adjacent the enlarged end of the valve seats in the rim opening. The pulling rod is then unthreaded or unscrewed from the valve threads and removed, leaving the new valve stem seated in place.
In a preferred and improved embodiment of the invention, the increased diameter section of the insertion tube containing the beveled conical or funnel shaped interior section is a separate piece which can be removed from the end of the insertion tube after the resilient or rubbery portions of the valve stem is completely drawn into or encompassed in the insertion tube. The end of the insertion tube is then placed in the rim opening and the pulling rod, which is still threaded onto the valve stem, is then used to push the valve stem through the rim opening. The insertion tube is then pulled up, or the pulling rod and such rod is used to pull the valve stem back through the rim opening until it seats in such rim opening whereupon the pulling rod is unscrewed from the pulling rod and the installation of the new valve stem is complete.
In the earlier and less preferred embodiment of the invention, the conical or funnel shaped interior section of the insertion tube is contained in a permanent enlarged portion of the insertion tube and as a result, after the valve stem is pulled into insertion tube, the pulling rod is unscrewed from the valve stem, the opposite smaller end of the insertion tube is placed in the rim opening after a strong line such as nylon line is tied to the threads of the valve stem and a special pusher rod or alternatively the end of the puller rod, is used to push the valve stem through the rim opening into the interior of the tire. The thin line is then used to retrieve the valve stem and draw its threaded end back to the rim opening whereupon the pulling rod is re-threaded to the valve stem and is pulled back through the rim opening as in the first embodiment until seated in the opening.